At least 10 killer whales were spotted late Sunday afternoon and again Monday morning off the Palos Verdes Peninsula, stealing the spotlight from migrating gray whales.

They're the same orcas that appeared in the same area on Dec. 10, and a day later off Newport Beach, and the increasing frequency of their visits suggests that transient killer whales are expanding their range into Southern California.

"There's no question that sightings are increasing," said Alisa Schulman-Janiger, who runs the California Killer Whale Project and catalogues individual orcas based on distinct markings. "Especially with the 51s. They seem to have become really fond of this area."

The killer whales spotted Sunday and Monday are from at least two family groups: the CA51s (seven whales) and CA 140s (three whales). There might have been two others, from the CA50 group. These groups are most commonly seen off Monterey in Central California.

Transient killer whales prey largely on marine mammals, especially sea lions, which abound off Southern California. They were first documented off the region in 2000. The CA51s, which often travel with a smaller family groups, have been sighted off Southern California at least a dozen times during the last two years.

They're famously boat-friendly, which makes for easy close encounters when they're around.

Interestingly, another marine mammal-eating group of killer whales, the L.A. Pod, shifted inexplicably from Southern California to Mexican waters in the 1990s.

It could be that over time, transient orcas began to feel more comfortable visiting the region. "The L.A. Pod was the only gang in town," Schulman-Janiger said. "If the L.A. Pod shifted to Baja, that could have left niche to be filled. It could be that this group [of transients] made a foray down here and found a lot of goodies. Most times they come down they're documented killing sea lions. "

On Sunday, Volunteers manning the Point Vicente Interpretive Center patio for the ACS/LA Gray Whale Census and Behavior Project witnessed the orcas breaching, spy-hopping and lob-tailing. Passengers aboard commercial whale-watching boats enjoyed much closer views, and in one case a baby orca seemed to have rubbed against the hull of a whale-watching boat.

Diane Alps, who was aboard the First String on Sunday, provided the accompanying image, showing a mother orca and her young calf.

Visibility on Monday morning was hampered by dense fog, but when the fog dissipated, there were the orcas, two-plus miles offshore, traveling to the southeast, possibly toward Orange County.

--Image is courtesy of Diane Alps

--Note: Schulman-Janiger would like to see fresh killer whale images and can be reached at Janiger@cox.net